The present invention relates to an electrical connector provided with a coiled spring contact (CSC). The connector is typically used by being interposed between two units or two circuit boards in an electronic device such as a mobile phone, thereby to perform electrical connection between connecting electrodes provided in both such units or circuit boards.
FIG. 5 shows a connector C provided with a coiled spring contact (hereinafter referred to as a CSC type connector) which is disclosed in Japanese Patent Publication No. 2002-93494A Here is shown, as an example of use, a state where the CSC type connector C is employed for connection between a liquid crystal display board 5 and a circuit board 6 in a mobile information terminal device such as a mobile phone. Specifically, connection electrodes 5C provided on the liquid crystal display board 5 and connection electrodes 6c provided on the circuit board 6 are electrically connected by the connector C.
As shown in FIGS. 6A and 6B, the connector C is provided with two CSCs 1 having electrical conductivity and with an insulating holder 2 which holds these CSCs 1 in a state arranged at an interval in an axial direction thereof.
As shown in FIG. 5, each of the CSCs 1 is adapted to come into elastic contact with a pair of the connection electrodes 5c, 6c which are opposed to each other in a radial direction of the CSC. More specifically, as shown in FIGS. 5 to 7B, the CSC 1 includes a pair of end coil parts 10 adapted to come into contact with the connection electrode 6c, and a central coil part 12 which is displaced in a radial direction between each end coil part 10 and adapted to come into contact with another connection electrode 5c. The CSC 1 further includes intermediate coil parts 14, 16 between the respective end coil parts 10 and the central coil part 12. In this case, the intermediate coil parts 14, 16 and the end coil parts 10 are arranged at both sides of the central coil part 12 in such a manner that they are gradually displaced in a radial direction at substantially equal intervals, and so, an entirety of the CSC 1 has a substantially inverted V-shape, as seen in a side view.
Because respective axes of the end coil parts 10, the intermediate coil parts 14, 16, and the central coil part 12 are in parallel with one another, and a direction common to these axes is defined as the axial direction of the CSC 1. Moreover, a direction perpendicular to the axes of the end coil parts 10, the intermediate coil parts 14, 16, and the central coil part 12 is defined as the radial direction of the CSC 1.
As shown in FIGS. 6A and 6B, the holder 2 is provided with openings 20 in a rectangular shape in both upper and lower faces thereof, through which portions of the end coil parts 10 and the central coil parts 12 to be contacted with the connection electrodes (portions of an outer periphery of the CSC) are respectively protruded outward. Moreover, the holder 2 has partition walls 21, 21′ for respectively interposing the CSCs 1 in the axial direction. By making a distance L between these partition walls substantially equal to a length t of the CSC 1 in the axial direction, the CSC 1 is restricted from being deformed or moved in the axial direction. Insulation between the two adjacent CSCs 1 is ensured by these partition walls 21, 21′.
When the liquid crystal board 5 and the circuit board 6 are pressed, as shown in FIG. 5, onto the connector C in a state as shown in FIG. 6B, the CSCs are elastically deformed so that a distance d between the respective axes of the central coil part 12 and the end coil parts 10 (an amount of displacement) decreases.
The partition walls 21, 21′ of the holder 2 are respectively provided with projections 22 which enter into the respective end coil parts 10 of the CSCs 1 in the axial direction. Each of the projections 22 has a slant face 22a at an upper side and a horizontal face 22b at a lower side, as shown in FIG. 6B. By reducing, to some extent, a length of the projection 22 in the radial direction of the end coil part 10, the CSC 1 is made possible to move in a displacing direction within a certain range, as shown in FIG. 6B.
According to the above described structure, when the aforesaid connection electrodes 5c, 6c are pressed onto the CSC 1 held by the holder 2 so as to clamp it from above and below in the radial direction, the CSC 1 will be elastically deformed only in the displacing direction, without being deformed and moved in the axial direction.
However, in mounting and positioning the connector C on the circuit board 6 (in order to secure electrical connection with the connection electrode 6c) in the above described structure, soldering work is employed. In this case, there has been such a possibility that solder or flux in a melted state may be sucked up by the CSC 1 by capillary force and may intrude into gaps between the respective coil parts. Thereafter, the solder or flux in the melted state may be hardened and adhered to the coil parts, and elastically deformable performance of the CSC 1 will be lost. To avoid such a problem, it is necessary to provide a separate positioning member in mounting the connector C on the circuit board 6.